"https://" is only required, when you use SME 6.5 RC1 (or SME 7.0?).
On SME 6.01 a "http://ip-address/server-manager" call should indeed do the trick.
If not, check the TCP/IP config. Ping the Server ip-address from the client, ping the client from the server, check the cables, the proper network mask, gateway and so on. Post them here, if you have further questions.